And even the common use of hashtags like #climatechange doesn’t mean that rivals are soaking in different viewpoints.

Hywel Williams, a scientist at the University of Exeter, said he was “blown away” by the findings, based on analysis of 590,608 tweets from 179,180 users between January-May 2013.

“It’s about who interacts with who. There’s a sense there is a debate and that people are interacting across ideological divides – and it turns out it’s not like that,” he told RTCC.

Many users are simply “preaching to the choir” said Williams, who identified two clear if different sized “clusters” of tweeters using five hashtags chosen for the study: #globalwarming, #climatechange, #agw (an acronym for ‘‘anthropogenic global warming’’), #climate and #climaterealists.

“We find that most individuals engaged in online discussions are embedded within communities of like-minded users; such self-reinforcing ‘‘echo chambers’’ can prevent engagement with alternative viewpoints and promote extreme views,” the study said.

The findings have implications for campaign groups seeking to influence policy decisions via social media, suggesting simply tweeting slogans to followers who already agree could be a waste of time.

There is little middle ground in the climate debate on twitter, the study found. “You only do it if you have a strong opinion,” said Williams.

Tweeters with influence include scientists, bloggers, campaigners and a few journalists, but few managed to bridge the divide between those who back climate science and those who remain sceptical.